Computer Registry doesn't register.

So I install a program right, and it appears in the Add/Remove program listing, and when I try to remove or edit my registry and such, after a restart the same **** happens like I didn't even do anything. Anything I install will register, except when I reboot, the program is still there, BUT its like it doesnt read it at all. I'm not sure if I make any sense at all. If you guys have any SOLUTIONS, it'd be appreciated otherwise I'll just reformat :blackeye:
System specs are as followed:
P4 1.7GHZ
512 Ram
Windows 2000
NVIDIA 6200
And not quite sure what else I should post.

Ok let me try to rephrase. When I do anything to alter the registry like install a new program, it appears in the registry and such and add/remove programs listing, but when I reboot it's like nothing I did ever happened. It doesn't appear in the add/remove program. Same with uninstalling a program. After I uninstall a program and then a reboot its still listed, but all the files are removed for that program. When I try to manually remove the string value for a program it comes back after a reboot. Hope that makes any sense

Edit: Also when I enter a serial key for a program, any program, after a reboot it asks for it again.^^

This happened a few weeks ago just slightly a few days after I Installed a new videocard.

Do you have full Administrator rights in W2K or are you just a normal User?
Only Admins can (un)install all programs, Users can only (un)install some (or none at all, depending on permissions allowed).